title: Isolation, purification, and partial characterization of suppressin, a novel inhibitor of cell proliferation.
abstract: Pituitary tissues were investigated for the presence of regulatory molecules that would alter the function of lymphoid cells. A novel endogenous polypeptide inhibitor of basal and mitogen-stimulated splenocyte DNA synthesis and proliferation, suppressin, was isolated from bovine pituitary glands. Suppressin is a potent inhibitor of basal and mitogen-stimulated splenocyte proliferation at picomole and nanomole concentrations with 50% inhibition occurring 2.8 x 10(-9) M. Suppressin was purified to apparent homogeneity using sequential (NH4)2SO4 precipitation, ion-exchange chromatography, and preparative native gel electrophoresis. Biochemical characterizations of suppressin showed that this inhibitory molecule was a monomeric polypeptide with (i) a Mr = 63,000 and (ii) a pI of 8.1. Finally, metabolic labeling studies using a rat pituitary tumor cell line, GH3, showed that suppressin was synthesized de novo and secreted by these cells.
authors.affiliation: Department of Physiology and Biophysics, University of Alabama, Birmingham 35294.
authors.forename: R D
authors.initials: RD
authors.lastname: LeBoeuf
authors.forename: J N
authors.initials: JN
authors.lastname: Burns
authors.forename: K L
authors.initials: KL
authors.lastname: Bost
authors.forename: J E
authors.initials: JE
authors.lastname: Blalock
mesh_terms: D000645:Ammonium Sulfate; D000818:Animals; D000906:Antibodies / Q000276:immunology; D000941:Antigens / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D011232:Chemical Precipitation; D002852:Chromatography, Ion Exchange; D003208:Concanavalin A / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis*; D004591:Electrophoresis, Polyacrylamide Gel; D008070:Lipopolysaccharides / Q000494:pharmacology; D008214:Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D008970:Molecular Weight; D010455:Peptides / Q000276:immunology / Q000302:isolation & purification* / Q000494:pharmacology; D010902:Pituitary Gland / Q000032:analysis*; D010911:Pituitary Neoplasms / Q000378:metabolism; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: D000906:Antibodies; D000941:Antigens; D008070:Lipopolysaccharides; D010455:Peptides; D003208:Concanavalin A; D004247:DNA; D000645:Ammonium Sulfate